Phenolic compounds

In this study, the extraction of chlorogenic acid from Vietnamese green coffee beans was optimized using the response surface methodology. A second-order polynomial model with three important variables (liquid-to-solid ratio, temperature, and extraction time) was used.

11p vibecca 01-10-2024 2 2   Download

This study aimed to quantify the phenolic contents and the antioxidant capacities of leaf extract powders from three Myrtaceae plants, namely Cleistocalyx operculatus (Vietnamese name: Vối), Psidium guajava (Ổi), and Rhodomyrtus tomentosa (Sim), investigate their inhibitive activities on the growth of bacteria isolated from spoiled shrimps, and evaluate their values as preservative agents in the cold storage of Pacific whiteleg shrimps (Penaeus vannamei).

15p vibecca 01-10-2024 3 2   Download

In Vietnam, a tea-producing country, the tea buds and top three leaves are normally used for tea production while older leaves are pruned and discarded as agricultural waste in the winter. The present study aimed to exploit catechins from pruned tea leaves and use them as natural antioxidants for applications in the food industry.

12p vibecca 01-10-2024 4 2   Download

Phytochemical study of Knema saxatilis stems led to the isolation of six known compounds. Their chemical structures were determined as 8-hydroxy eriodictyol (1), (2S)-7-hydroxy-3′,4′-methylenedioxideflavan (2), sitostenone (3), protocatechuic acid (4), 4-hydroxybenzoic acid (5) and vanillin (6) using NMR and MS spectral data.

7p viyoko 01-10-2024 1 1   Download

It can be seen that the objects of wastewater that need to be treated are quite diverse in types and complex in terms of reaction mechanisms. The methods mainly focus on the treatment of toxic organic compounds, especially phenols or plant protection agents in industrial wastewater, paper industry, food production, textile industry, printing industry.

6p vikwong 29-09-2024 4 0   Download

Avocado peel has been considered as a potential source of natural antioxidants in which phenolics are among the most important compounds. Therefore, this study aims to optimize the extraction process of phenolics using response surface methodology and evaluate the corresponding antioxidant activity.

11p vifaye 20-09-2024 2 1   Download

The methanol extracts as well as some compounds from this plant exhibited anti-inflammatory, antimicrobial activity, antioxidant, hepatoprotective and anti-cancer effect, and antiosteoporotic. On going to search for bioactive components from the Vietnamese plant, this paper reported the isolation of seven phenolic compounds including one new from the aerial parts of A. ilicifolius. The cytotoxic activity of the isolates against two cancer cell lines (HepG2 and SK-LU1) were also screened and reported herein.

5p dianmotminh02 03-05-2024 8 2   Download

Master's thesis of Science "Investigation into the modulation of circadian clock proteins by dietary compounds and small molecules" is structured as follows: Chapter 1 Introduction; Chapter 2 Identification of novel bioactive compounds from Olea europaea by evaluation of chemical compounds in the OliveNetTM library: in silico bioactivity and molecular modelling, and in vitro validation of hERG activity; Chapter 3 Modulation of circadian core clock proteins by dietary compounds; Chapter 4 Molecular mechanisms of action of selected olive phenolics against epigenetic modifiers and the structur...

235p runthenight04 02-02-2023 4 2   Download

Fractions yielded from Phellinus gilvus fruiting bodies by liquid-liquid partition of methanol extract contained various bioactive compounds such as phenolics, flavonoids and terpenes. Butanol, water and ethyl acetate fractions had large amount of phenolics, 158.12 - 247.31 mg of gallic acid equivalents (GAE)/g and low amount of flavonoids, 21.74 - 36.05 mg of quercetin equivalents (QE)/g.

9p vimelindagates 18-07-2022 12 3   Download

Response surface methodology was applied to optimize the extraction of phenolic compounds from fresh Pouzolzia zeylanica plant using hot water as a solvent. A central composite design (CCD) in form (23+star) was used to investigate the effects of two independent variables, namely, extraction temperature (70 to 90oC) and extraction time (20 to 40 min).

10p larachdumlanat129 19-01-2021 19 2   Download

Ricinus communis Linn. (Castor oil plant) is a monotypic species of Ricinus genus (Euphorbiaceae) and widely distributed in all tropical countries. Phytochemical data of this plant are scarce. As part of ongoing research on a survey of Vietnamese medicinal plants, the investigation of this plant was performed. The isolation and structural determination of five phenolic compounds isolated from the leaves of R. communis Linn. growing in Binh Phuoc province were addressed.

5p larachdumlanat127 02-01-2021 8 2   Download

The study revealed that the tested compounds are moderate UVB absorbers, but could be used to augment the effect of other photoprotective agents. Their SPF values were in the range from 3.63 to 4.26 for salicylates 3a-d and from 3.03 to 3.51 for vanillates.

10p tocectocec 25-05-2020 10 2   Download

Từ 4,5-đimetoxi-2-(3-metylfuran-4-yl)phenylamine, đem điazoni hóa sau đó ghép với các amin và phenol thơm tạo thành 8 hợp chất azo. Cấu trúc của các hợp chất này được các định bằng các phương pháp phổ IR, 1H NMR, 13C NMR, HSQC, HMBC. Đã thử hoạt tính kháng vi sinh vật kiểm định của 3 hợp chất. Fom 4,5-dimethoxy-2-(3-methylfuroxan-4-yl)phenylamine, diazonium and followed by pairing with aromatic amines and phenols to obtain 8 azo compounds. These compounds have been measuredby IR, 1H RRN, 13C NMR, HSQC, HMBC to determine their structuresand.

6p khidoichuoi 04-03-2020 74 4   Download

In this study, the effect of extraction conditions on the antioxidant activity of Vernonia amygdalina Del. (Asteraceae) was evaluated by Response surface methodology and central composite design (RSM-CCD) to predict the content of phenolic compounds with maximum antioxidant activity.

10p quilen 30-11-2019 23 2   Download

Helicteres hirsuta Lour., particularly its stems and leaves have been used in Vietnamese traditional medicine to cure furuncles, dysentery, measles and flu. In this study, we examined biological activities of 5 fractions from methanol extract of H. hirsuta roots. The results showed that ethyl acetate fraction has the highest content of phenolic and flavonoid compounds (220.9 ± 15.67 mg GAE, gallic acid equivalents/g dry weight and 23.03 ± 0.97 mg QE, quercetin equivalents/g dry weight, respectively).

7p shiwo_ding7 05-06-2019 42 2   Download

A study of wine fermentation from mucilage of cocoa beans (theobroma cacao l.). Cocoa mucilage, a by-product of cocoa beans processing, constitutes 10% of total cocoa beans, with soluble solids up to 17.78 Bx, pH of 3.43 – 3.5, rich in sugar, minerals, organic acids and phenolic compounds.

11p lehasiphuong 22-05-2018 97 4   Download

Sugar conjugation is a major pathway for the inactivation and excretion of both endogenous and exogenous compounds. We report here the molecular cloning and functional characterization of a phenol UDP-glucosyltransferase (UGT) from the silkworm, Bombyx mori, which was named BmUGT1. The complete cDNA clone is 1.6 kb, and the gene is expressed in several tissues of fifth-instar larvae, including fat body, midgut, integument, testis, silk gland and haemocytes. The predicted protein comprises 520 amino acids and has  30% overall amino-acid identity with other members of the UGT family.

7p research12 01-06-2013 39 4   Download

To investigate how solubility and steric issues affect the laccase-catalysedoxidationof phenols, a series of oligomeric polyphenol compounds, having increasing size and decreasing solubility in water, was incubated with laccase. The extent of substrate conversion, and the nature of the products formed in buffered aqueous solutions, were com-pared to those obtained in the presence of an organic cosolvent, and also in the presence of twomediating species, i.e. N-hydroxyphthalimide (HPI) and 2,2,6,6-tetramethyl-piperidin-1-yloxy (TEMPO). ...

6p tumor12 22-04-2013 40 2   Download

The sulfonephthalein indicator, phenol red, exhibits an unusually slow rate of oxidation by laccase fromPolipo-rus pinsitus, in spite of the fact that it is a phenol and therefore a natural substrate for this phenoloxidase enzyme. Nevertheless, after prolonged exposure to laccase (24 h) phenol red is oxidized by more than 90%.

7p tumor12 20-04-2013 40 2   Download

CYP73 enzymes are highly conserved cytochromes P450 in plant species that catalyse the regiospecific 4-hydroxylation ofcinnamicacid to formprecursorsofligninandmanyother phenolic compounds. A CYP73A1 homology model based on P450 experimentally solved structures was used to iden-tify active site residues likely togovern substrate binding and regio-specific catalysis. The functional significance of these residues was assessed using site-directedmutagenesis.

12p tumor12 20-04-2013 40 3   Download